kernel/arch/s390/boot/mem_detect.c, branch linux-6.2.y

s390/boot: fix mem_detect extended area allocation

2023-03-10T08:28:16Z

[ Upstream commit 22476f47b6b7fb7d066c71f67ebc11892adb0849 ] Allocation of mem_detect extended area was not considered neither in commit 9641b8cc733f ("s390/ipl: read IPL report at early boot") nor in commit b2d24b97b2a9 ("s390/kernel: add support for kernel address space layout randomization (KASLR)"). As a result mem_detect extended theoretically may overlap with ipl report or randomized kernel image position. But as mem_detect code will allocate extended area only upon exceeding 255 online regions (which should alternate with offline memory regions) it is not seen in practice. To make sure mem_detect extended area does not overlap with ipl report or randomized kernel position extend usage of "safe_addr". Make initrd handling and mem_detect extended area allocation code move it further right and make KASLR takes in into consideration as well. Fixes: 9641b8cc733f ("s390/ipl: read IPL report at early boot") Fixes: b2d24b97b2a9 ("s390/kernel: add support for kernel address space layout randomization (KASLR)") Reviewed-by: Alexander Gordeev Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

s390/mem_detect: rely on diag260() if sclp_early_get_memsize() fails

2023-03-10T08:28:16Z

[ Upstream commit eb33f9eb304a4c18beb5ba6362eaa5c4beaf40d8 ] In case sclp_early_get_memsize() fails but diag260() succeeds make sure some sane value is returned. This error scenario is highly unlikely, but this change makes system able to boot in such case. Suggested-by: Alexander Gordeev Reviewed-by: Alexander Gordeev Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens Stable-dep-of: 22476f47b6b7 ("s390/boot: fix mem_detect extended area allocation") Signed-off-by: Sasha Levin

s390/mem_detect: fix detect_memory() error handling

2023-03-10T08:28:15Z

[ Upstream commit 3400c35a4090704e6c465449616ab7e67a9209e7 ] Currently if for some reason sclp_early_read_info() fails, sclp_early_get_memsize() will not set max_physmem_end and it will stay uninitialized. Any garbage value other than 0 will lead to detect_memory() taking wrong path or returning a garbage value as max_physmem_end. To avoid that simply initialize max_physmem_end. Fixes: 73045a08cf55 ("s390: unify identity mapping limits handling") Reported-by: Alexander Gordeev Reviewed-by: Alexander Gordeev Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

s390/boot: get rid of startup archive

2022-05-06T18:45:14Z

The final kernel image is created by linking decompressor object files with a startup archive. The startup archive file however does not contain only optional code and data which can be discarded if not referenced. It also contains mandatory object data like head.o which must never be discarded, even if not referenced. Move the decompresser code and linker script to the boot directory and get rid of the startup archive so everything is kept during link time. Acked-by: Vasily Gorbik Signed-off-by: Heiko Carstens

s390/boot: introduce boot data 'initrd_data'

2021-07-27T07:39:15Z

The new boot data struct shall replace global variables INITRD_START and INITRD_SIZE. It is initialized in the decompressor and passed to the decompressed kernel. In comparison to the old solution, this one doesn't access data at fixed physical addresses which will become important when the decompressor becomes relocatable. Signed-off-by: Alexander Egorenkov Acked-by: Heiko Carstens Signed-off-by: Heiko Carstens

s390/cio: remove unused include linux/spinlock.h from cio.h

2021-07-27T07:39:13Z

* The linux/spinlock.h header was included indirectly by the decompressor and brought unnecessary build dependencies. * Use proper includes in files which either directly or indirectly included cio.h and were hidden until now by the included linux/spinlock.h, e.g. linux/string.h for memcpy() or asm/page.h for PAGE_SIZE. Signed-off-by: Alexander Egorenkov Acked-by: Heiko Carstens Acked-by: Vasily Gorbik Signed-off-by: Heiko Carstens

s390/mem_detect: fix tprot() program check new psw handling

2021-06-18T14:41:24Z

The tprot() inline asm temporarily changes the program check new psw to redirect a potential program check on the diag instruction. Restoring of the program check new psw is done in C code behind the inline asm. This can be problematic, especially if the function is inlined, since the compiler can reorder instructions in such a way that a different instruction, which may result in a program check, might be executed before the program check new psw has been restored. To avoid such a scenario move restoring into the inline asm. For consistency reasons move also saving of the original program check new psw into the inline asm. Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/mem_detect: use register pair instead of register asm

2021-06-18T14:41:24Z

...and slightly cleanup the inline asm. Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/mem_detect: fix diag260() program check new psw handling

2021-06-18T14:41:24Z

The __diag260() inline asm temporarily changes the program check new psw to redirect a potential program check on the diag instruction. Restoring of the program check new psw is done in C code behind the inline asm. This can be problematic, especially if the function is inlined, since the compiler can reorder instructions in such a way that a different instruction, which may result in a program check, might be executed before the program check new psw has been restored. To avoid such a scenario move restoring into the inline asm. For consistency reasons move also saving of the original program check new psw into the inline asm. Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390: unify identity mapping limits handling

2020-11-20T18:19:10Z

Currently we have to consider too many different values which in the end only affect identity mapping size. These are: 1. max_physmem_end - end of physical memory online or standby. Always <= end of the last online memory block (get_mem_detect_end()). 2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the kernel is able to support. 3. "mem=" kernel command line option which limits physical memory usage. 4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as crash kernel. 5. "hsa" size which is a memory limit when the kernel is executed during zfcp/nvme dump. Through out kernel startup and run we juggle all those values at once but that does not bring any amusement, only confusion and complexity. Unify all those values to a single one we should really care, that is our identity mapping size. Signed-off-by: Vasily Gorbik Reviewed-by: Alexander Gordeev Acked-by: Heiko Carstens Signed-off-by: Heiko Carstens